Python vs. Lisp -- please explain

[Paul Rubin]

dlp at itasoftware.com writes:
> But Lisp isn't dynamically typed "exactly the way Python is".
> Python documents ways to manipulate the internals of objects at
> runtime.  It is possible to add, change or delete methods and slots
> by directly changing the hashtable they're stored in.  While CLOS
> does permit a certain amount of runtime redefinition, it is not as
> completely free wheeling and unpredicatable.

Although CLOS is now part of the Lisp standard I haven't generally
thought of it as describing the language semantics.  It's more like a
library routine.  Python's standard library generally doesn't provide
documented ways of mucking around with the internal structure of
library classes.  CLOS (or something close to it) similarly can and
has been implemented as a Lisp macro package independent from the rest
of the Lisp system.